Seat shell for seating furniture

ABSTRACT

The invention provides for a seat shell for seat furniture, in particular chairs, comprising a shell top and a shell base, said shell top has a substantially closed surface. The surface of the shell top has a surface structure with a plurality of intersecting recesses which form ventilation channels.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of International Application No. PCT/EP2012/059337, filed on May 21, 2012, which claims priority to German Patent Application No. 10 2011 076 196.9, filed on May 20, 2011, the contents of each of which are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a seat shell for seating furniture, especially chairs, with a shell top and a shell base side.

BACKGROUND

Seat shells for seating furniture with a shell top and a shell base side are known from the prior art. For example, seat shells made from plastic material are known whose internal volume is designed as a hollow body. It is known to provide openings in the surface forming the seat surface which lead into the interior volume or in the cavity of the seat shell in order to achieve a certain ventilation effect and hence to reduce the perspiration of the user.

Adequate ventilation of the seat surface is yet not achieved, especially not if all openings on the seat surface are covered by the seated person, since the openings only lead into the cavity of the seat shell, therefore preventing or at least impeding circulation of air or an air exchange. Another disadvantage is that the openings allow the arrival of any kind of dirt, but also of liquids into the cavity of the seat shell, which may also clog the apertures himself. A cleaning of the interior of the seat shell is not possible or possible only with great difficulties. This is particularly disadvantageous when the seat shell is to be used for seating furniture in the school system where high demands are placed on hygiene.

The object of the present invention was therefore to provide a seat shell for seating furniture, in particular chairs, which avoids the disadvantages known from the prior art and which in particular do allow for an improved ventilation of the seat surface.

SUMMARY

According to the invention, this problem is solved by a seat shell for seating furniture, especially for chairs, according to the independent claim. Advantageous embodiments of the invention emerge from the dependent claims.

Accordingly, the invention provides a seat shell for seating furniture, especially chairs, comprising a shell top and a shell base side. The shell top has a substantially closed surface, whereby the surface of the shell top has a surface structure with recesses which form channels for the passage of air.

Thus, in an advantageous manner a ventilation in the area of the shell top is ensured as a circulation of air from one end of the recession to the other end of the recession is maintained even when a person sits on the seat shell, because of the recessions, forming channels or ventilation grooves respectively. In addition, it is prevented that dirt can enter the interior of the shell, because openings in the shell top into the cavity of the seat shell can be avoided. The recessions are preferably designed or formed in such a way that the seated person does have no unpleasant sensation. Instead, the seated person generally does feel the haptic impression created by the rest of the surface structure of the shell top.

It is especially preferred when the recesses in the seating area do have a width of between 5 mm and 20 mm. At this width, sufficient ventilation function can be provided while easy accessibility of the recesses is guaranteed for cleaning purposes.

It has been found to be advantageous when the surface structure of the shell top comprises a plurality of intersecting recesses. The intersecting recessions can form a network structure. The recessions may intersect at an angle of about 60° but different at an angle other than 60°. It can also be the case that more than two elongated recesses intersect at one point.

The non-recessed areas of the surface structure form the bearing surfaces of the shell top. The bearing surfaces together form the seat area, or that side facing the back of a person forming the backrest. The intersecting elongated recesses provide a further improved ventilation of the shell top. The transitions between the recesses and the seating surface or respectively that side, facing the back of a person and forming the backrest, are substantially rounded.

It has been found particularly advantageous when at least one recession in the surface structure does extend up to an outer edge of the shell top. As a consequence, the ventilation function is maintained substantially independent from the seating position.

The elongated recesses may have a substantially smooth surface, preferably with no edges and corners. Thus, cleaning of the elongated recesses is substantially simplified.

The seat surface forming part of the shell top can be curved in the front region in the center in a saddle shape, wherein the curvature may extend beyond the front edge of the shell top. Thus, a common seating position among students, namely sitting very close to the front of the chair, is supported.

The backrest forming part of the shell top may have a vertical spine recess in the central region. The spine recess may widen up to the upper part. In one embodiment of the invention, the spine recess in the lower region has a width between 30 mm and 100 mm and a width between 20 mm and 60 mm in the upper region.

According to a further embodiment of the invention, the spinal recess may be tapered to the top.

Thus, a more pleasant and ergonomic seating is made possible, whereby an adequate ventilation also at the backrest forming part of the shell top is ensured at the same time by the recesses in the shell top.

The depth of the spine recession may correspond substantially to the depth of the recessions on the surface structure. Preferably the spine recess intersects at least some of the recessions of the surface structure, so that an air circulation is possible also in the region of the spine recession.

The backrest may comprise a grip hole to allow easy carrying of the chair. The grip hole is preferably situated in the lower range, even more preferred in the lower third of the backrest. Thus it is also possible for children to carry the chair in an ergonomic and power saving manner.

The shell base side may comprise a recess which is configured stronger and into which a part of a seat support can be arranged in a substantially positive fitting.

Further provided is a seat shell for seating furniture, especially chairs, with a seat shell made of plastic, wherein the backrest comprises a grip hole, to which at the rear of the backrest a downwardly extending recess is adjoined, that recess being continued to the underside of the shell base side, wherein the width the recession substantially corresponds to the width of the grip hole. In the recess of the recess, the backrest has a lower thickness than in the remaining region.

The recess is forming bars being substantially parallel to each another and downwardly extending, which connect ideally to the bars formed by the grip hole. The bars are continued preferably at the underside of the shell base side.

Thus, both the backrest and the transition region between the seat and backrest gain additional stability, allowing in particular for plastic chairs the use of less material while maintaining high stability, which is especially necessary for school furniture. In addition, the grip hole forms of a large contact area at its top, because the recession is not maintained above the grip hole, so that an ergonomic lifting of the chair is made possible.

Preferably the width of the seat shell in the transition region between the seating surface and backrest is less than the width of the seating surface and the backrest. Thus, a very popular sitting position among students, namely sitting on the chair twisted around, is supported.

It has been found to be advantageous to arrange for drawn down blankets at the outer edges of the seat shell in the transition region between the seat and backrest. In case a child is sitting on the chair in a twisted position, an unpleasant sensation in the thigh area is avoided, because the blankets are a very good surface for the femur. Moreover, the rigidity of the seat shell in the transition region is further improved.

The upper end edge of the backrest can be designed bead like, wherein the bead is extending substantially only at the rear of the backrest. This is on one side an additional possibility to carry the chair whereas on the other side the rigidity of the seat shell in the area of the top end edge of the backrest improves.

A further advantage results from the formation of a finger grip recess in the lower region of the backrest, preferably below the seat. This makes it possible to take the chair at a low point and raise it, thus easing the raise up to higher altitudes—for example when stacking chairs. This a special advantage for smaller people, particularly school children.

A hollow body is formed by the shell top and the shell base side. The shell base side may have at least one opening through which an exchange of air between the hollow body and the environment is possible. This opening in the shell base side warrants that the hardness or flexibility of the shell top and in particular the seat surface forming part of the shell top is defined substantially by the material of the shell top, without influencing the hardness or flexibility of the shell top by the internal pressure of the hollow body.

In one embodiment of the invention the wall thickness of the shell top is smaller than the wall thickness of the shell base side. Thus, the shell top can be made more flexible and soft, while the shell base side is harder and stronger and takes over the function of holding the seat. The hardness or flexibility of the shell top and the shell base side can be determined essentially by the respective wall thickness.

The shell base side of the seat shell may have a recess, which may be designed reinforced and in which a part of a seat support can be arranged in a substantially positive fitting. Thus, the mount of a seat support is greatly facilitated.

The shell base side side and/or the shell top can be made by injection moulding, by using blowing process and/or by a cupping process and/or by a rotary casting process. Shell base side and shell top may be manufactured separately from each other, for example using the cupping process, then being connected subsequently.

Preferably, the seat shell is designed in one piece.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and features of the invention will become apparent from the following description in conjunction with the drawings. In the drawings:

FIG. 1 shows an inventive seat shell in an isometric angular view from above;

FIG. 2 shows the inventive seat shell of FIG. 1 in a view from below;

FIG. 3 shows the inventive seat shell of FIG. 1 in a view from above;

FIG. 4 shows the inventive seat shell of FIG. 1 in a side view;

FIG. 5 shows the inventive seat shell of FIG. 1 in a view from the front;

FIG. 6 shows the inventive seat shell of FIG. 1 in a view from the rear; and

FIG. 7 shows an inventive seat shell, which in arranged on a seat support, in an isometric view from below.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an inventive seat shell in an isometric angular view from above.

The seat shell 10 comprises a shell top 20 and a shell base side 30. Preferably the seat shell is made of plastic. The shell top 20 and the shell base side 30 can be each prepared by a thermoforming or an injection molding process and are subsequently assembled. Alternatively, the seat shell 10 can be manufactured in one piece by an injection blow molding process. Alternatively, the shell top 20 may be made of a plastic material and the shell base side 30 from a stable material, such as metal.

The shell top 20, forming the seating surface 25 and that part of the back rest 26, facing the person's back, comprises a plurality of recesses 22. Those recesses form ventilation grooves or channels for the passage of air.

In the example shown in FIG. 1, several elongated recesses 22 extend from the right side of the shell top 20 to the left side of the shell top 20. Furthermore, several elongated recesses 22 extend from the rear portion of the seat surface 25 to the front area of the seat surface 25, wherein these elongated recesses do cross those recesses extending from the right side of the shell top to the left side of the shell top 20. Furthermore, elongated recesses across the seat surface are provided. The non-recessed portions 23 of the shell top have, according to the embodiment of the seat shell shown in FIG. 1, a substantially triangular shape.

In another embodiment not shown here, only longitudinal recessions or only recessions transverse the seating surface may be provided.

The seating surface of the shell top 20 is formed by the non-recessed regions 23. The transitions between the recessions 22 and the non-recessed areas 23 are preferably rounded so that no unpleasant sensation is caused by the recessions when sitting on the seat shell.

In addition, the top shell 20 has in the region of the backrest several elongated recessions 22 which extend from the upper region of the backrest to the lower region of the backrest. Also in the area of the back rest those recessions 22 extending from the top to the bottom 2 cross those recessions 22, extending from right to left. Similarly, also in the region of the backrest transverse recesses 22 may be provided. The transitions between the recesses 22 and the non-recessed areas 23 are rounded also in the region of the backrest.

In the area of the seating surface, recesses do have a maximum width of 20 mm. They preferably have a maximum width of 10 mm. Particularly preferred, a width of the elongated recesses 22 of about 6 mm to about 10 mm is chosen. That provides for a sufficiently good ventilation function of the seating surface respectively the shell top whereas on the other hand the elongated recesses 22 are sufficiently wide in order to allow for a proper cleaning of the recessions 22. Moreover, depending on the surface structure, up to a maximum width of the elongated recesses 22 of 20 mm, it is ensured that no unpleasant sensation due to broad recessions 22 is created.

The recessions extending from the right side of the shell top 20 to the left side of the shell top 20 preferably extend up to the right outer edge or to the left outer edge of the shell top 20 respectively so that sufficient air circulation is guaranteed, therefore allowing for a proper ventilation function of the shell top regardless of seat position.

The distance between the elongated recesses is chosen so that a comfortable sitting on the seat surface, which is formed by the non-recessed regions 23, is ensured and, at the same time, that a sufficiently good ventilation function over the entire area of the shell top 20 is ensured also.

On that side of backrest of the shell top 20, facing the dorsum, a spine recess 28 is provided, into which the spine finds clearance at least partially in order to avoid an unpleasant pressure of the backrest against the spine far as possible. The spine recess 28 has a width in the lower region of about between 30 mm and 100 mm and tapers towards the top, where it has a width of about between 20 mm and 60 mm.

In a further embodiment not shown here the spine recess 28 in the lower region may also be formed more narrow than in the upper region. Also conceivable is an embodiment with a parallel spine recess 28, that is a recess with substantially constant width.

The spine recess 28 provides substantially the same depth as the elongated recesses 22 in the back rest of the shell top 20. The spine recess 28 may also be somewhat deeper than the elongated recesses 22.

In the shell top embodiment shown here, the spine recess 28 intersects the recesses 22 extending from right to left. Thereby also in the area of the spine recess 28, a proper ventilation is provided, as the recesses 22 extending from right to left provide for adequate air circulation in the area of the spine recess 28 also.

In the embodiment shown here, the top shell 20 is configured soft, while the shell base side 30 is harder and provides the necessary stability of the seat shell 10. The hardness of the shell top 20 and the shell base side 30 can be determined essentially by the material thickness, i.e. by the wall thickness of the shell top or the shell base side. It has been found to be advantageous to use a thin, slightly resilient material for the seat top 20, that therefore is a material supporting a soft seat position.

It is also possible to use plastic material for the shell top 20 and a stable material such as wood or metal for the shell base side 30. Alternatively, for the manufacture of the shell top and the shell base side 30 also composite materials such as plastic mixed with hemp fibers may be used.

The seat shell 10 provides for a curvature 27 in the front region of the seating surface 25, so that the seating surface 25 forms essentially a so-called saddle seat. Thus, a student at common sitting posture, namely sitting very far forward, can be supported.

The width of the seat shell in the transition region between the seat 25 and backrest 26 is smaller than that of the rest of the seat shell, i.e., less than the width of the seat surface 25 and the backrest 26. Thus, a very popular students sitting posture, namely twisted around to sit on the chair, can be supported, because the lower part of the backrest is ergonomically advantageous placed between the thighs. A detailed view of the transition region between the seating surface 25 and backrest 26 can be seen in the FIG. 5 and FIG. 6.

In order to support an ergonomic and comfortable sitting when sitting rotated around also, it is advantageous when the seat shell provides for blankets 45 at its outer edges in the transition region between the seating surface 25 and the backrest 26. The blankets 45 form an excellent surface for the femur, when a person turned around is sitting in the chair. In addition, the rigidity of the seat shell in the transition zone is also clearly improved by the blankets 45.

The backrest has a grip hole 40, to allow for easy carrying of the chair by engaging in the grip hole. The grip hole is preferably situated in the lower range, particularly preferred in the lower third of the backrest. Therefore it is also possible for children to carry the chair in an ergonomic and power-saving manner. In addition, the grip hole 40, which is located in the spinal recession 28, supports air circulation in the area of the backrest 26.

The upper end edge of the backrest 26 can be configured bead like, which will be described in greater detail with reference to FIG. 4. In addition, a recessed grip recess 49 may be formed in the lower region of the backrest, preferably below the seat surface. Such a low-lying grip allows to take and raise the chair at a low point, which allows to more easily raise the chair to greater heights—for example in order to stack the chairs—, which is especially in schools of great advantage, where many children, due to their smaller body size, have difficulties to cope with such tasks. Particularly advantageous is the combination of a bead like upper edge of the backrest 26 with such a low lying grip recess 49, as the chair can be handled specifically good and safe in that way.

FIG. 2 shows the seat shell 10 of FIG. 1 a view from below.

Visible here is the part of the shell base side 30, being opposite to the seating surface 25. Also visible here is the configuration of the shell base side 30, which allows to securely and stably attach the seat shell 10 to a seat support 35 or to a holder for a seat support. For this purpose, the lower part of the shell base side 30 provides for one or more recesses 50 into which a seat support 35 and a mounting for a seat support can be arranged with a substantially positive fit. The area of the recesses 50 can be designed more stable than the remaining area of the shell base side 30. The seat support 35 or a bracket can be fastened by means of a screw connection to the seat shell 10. Through the recesses 50, a simple mounting of the seat support 35 or the bracket is supported, because the seat support can be mounted with a positive fitting into the recesses 50, where it can remain until screwing the seat support in place. Of course it goes without saying that a conventional screw mounting, ideally with the help of additional metal plates, is possible also.

Furthermore, the shell base side 30, may, not shown here, comprise an opening which extends into the cavity between the shell top 20 and shell base side 30. Through the opening, air may escape from the cavity of the seat shell 10, which is particularly the case when someone sits on the (softer) shell top 20. Through by the exchange of air between the cavity and the surrounding it is ensured that the hardness or elasticity of the shell top 20 is determined substantially by the material of the shell top 20, as no back pressure can arise, counteracting the deformation of the shell top.

Preferably, the opening is provided at the shell base side, i.e. in the area of the shell base side 30 lying opposite to the seating surface of the shell top 20. Of course, the opening can also be arranged at the rear of the backrest, which, however, has the disadvantage that dirt can easily get into the cavity of the seat shell 10. The diameter of the hole is ideally about 20 mm. It is also possible to use—possibly several—smaller or larger openings, whereas the openings should not be so small that noise is arising when air is flowing through the openings.

In case of the use of wood or metal as a material for the shell base side 30, the openings in the shell base side also serve to reduce the weight of the seat shell.

FIG. 3 does show the seat shell 10 of FIG. 1 in a view from above. Clearly visible here is the texture of the shell top 20 with its recessions 22 along the shell top 20. Also visible here is the curvature 27 in the front region of the seating surface 25 which protrudes beyond the front edge of the shell top 20 so that the seat surface 25 substantially forms a so-called saddle seat.

FIG. 4 does show the seat shell 10 of FIG. 1 in a side view. At the top end edge of the backrest 26, a bead 48 is provided which extends substantially only at the rear of the backrest 26. Seen here is also the blanket 45 dragged down in the transition region between the seating surface 25 and the seatback 26 at the outermost right side of the seat shell 10. The blanket 45 on one hand improves the stability or rigidity of the seat shell 10 in the transition region. On the other hand, the leg can very well rest on the blanket 45 when a person sits in the chair turned around. The blankets 45 can also be shaped in such a way, i.e. rounded, that a lifting of the chair at those blankets causes no unpleasant sensations.

FIG. 5 shows the seat shell 10 of FIG. 1 in a front view. Seen especially well here is the configuration of the transition area between the seating surface 25 and the backrest 26. The width of the seat shell in the transition region is substantially less than in the remainder of the seat shell, so that if a person sits rotated on the chair, the transition region conveniently takes place between the thighs of the person.

FIG. 6 shows the seat shell 10 of FIG. 1 in a view from the rear. Visible are the pulled down and substantially rounded blankets 45 at the side.

The backrest 26 comprises at its back of a downwardly extending recess 46 which is continued to the base side of the seating surface. The continuation of the recession 46 on the base side of the seating surface is shown in FIG. 2. The recession 46 is bounded above by the grip hole 40 so that the upper end of the recess 46 directly emerges into the grip hole 40. The width of the recess 46 corresponds substantially to the width of the grip hole 40. By the recess 46 two substantially parallel formed downwardly extending bars 47 are formed at the back side of the backrest 26, which in the region of the grip hole 40, that is above the grip hole, are brought together. The bars 47 are continued on the base side of the seating surface.

The bars 47 will award the backrest and the transition region between the backrest and the seating surface additional stability, which is further improved by the blankets 45 pulled down at the side. An additional lower grip 49 forms a stop ridge at the same time, thus also contributing to the increased stability.

FIG. 7 shows a seat shell mounted on a seat support 35 which is designed as a Z-shaped cantilever in an isometric view from a downward position. Seen here is in particular the substantially form-fitting arrangement of the seat support 35 in the recess 50 at the shell base side 30. As an alternative to the Z-shaped cantilever, other cantilevers or other seat supports, such as four-legged seat supports may be used instead.

LIST OF REFERENCE NUMERALS

-   10 seat for seating furniture -   20 shell top -   22 air recessions (elongated dimples) on the shell top -   23 non recessed areas on the shell top -   25 the part of the shell top forming the seating surface -   26 the part of the shell top forming the backrest -   27 curvature -   28 vertical spine recession at the part of the shell top, forming     the backrest -   30 shell base side -   35 seat support and seat support bracket -   40 grip hole -   45 pulled down blankets (to the seat, rear left and right) -   46 recess at the rear of the backrest -   47 vertical bars at the rear of the backrest -   48 bead on the top end edge of the backrest -   49 lower recessed grip -   50 opening at the shell base side -   60 cross strut of a seat support -   70 connection element of a seat support 

What is claimed is:
 1. A seat shell (10) for seating furniture, especially chairs, comprising a shell top (20) and a shell base side (30), wherein the surface of the shell top (20) has a surface structure with a plurality of intersecting, elongate recesses (22), forming channels for the passage of air, whereas the non-recessed portions (23) of the surface structure form the seat area of the shell top (20).
 2. The seat shell of claim 1, wherein the shell top side (20) has a substantially closed surface and the shell base side (30) is substantially closed.
 3. The seat shell of claim 1, wherein at least one recess (22) extends up to an outer edge of the shell top (20), so that air can reach the channels (22) when the chair is in use.
 4. The seat shell of claim 1, wherein a part of the shell top (20) forming a seat area (25) is curved like a saddle in the front and central region wherein the curvature (27) extends beyond the front edge of the shell top (20).
 5. The seat shell of claim 1, wherein a part of the shell top (20) forming a backrest (26) comprises a vertical cavity for the spine (28) in a central region of the backrest.
 6. The seat shell of claim 5, wherein the backrest further comprises a grip hole (40), preferably in the lower range, particularly preferably in the lower third.
 7. The seat shell of claim 5, wherein the width of the seat shell in the transition region between the seat surface (25) and the backrest (26) is less than the width of the seat surface (25) and the backrest (26) and wherein substantially in the transition region between the seat surface (25) and backrest (26) the seat shell comprises drawn down blankets (45) at their outer edges.
 8. The seat shell of claim 5, wherein the upper end edge of the backrest (26) has a bead like structure, wherein the bead (48) is substantially extending at the rear of the backrest (26) only.
 9. The seat shell of claim 5, wherein in the lower region of the backrest (26), preferably below the seat surface (25), is formed a deepening (49) designed as a finger grip.
 10. The seat shell of claim 5, wherein the shell top (20) or the shell base side (30) is producible by injection molding, by a blow process, by a cupping process and/or in a rotary casting process.
 11. The seat shell of claim 5, wherein the shell is formed in one piece.
 12. A seat shell for seating furniture, especially chairs, wherein a backrest (26) comprises a grip hole (40), in a line with a downwardly extending recess (46) at the rear of the backrest (26), and wherein the recess is continued on the shell base side of a seat surface, wherein the width of the recess (46) substantially correlates to the width of the grip hole (40).
 13. The seat shell of claim 12, wherein the recess (46) is forming by surfaces substantially parallel to one another and downwardly extending bars (47) that preferably connect directly to a side bar formed by the grip hole and which are continued on the base side of the seat surface.
 14. The seat shell of claim 12, wherein the upper end edge of the backrest (26) has a bead like structure, wherein the bead (48) is substantially extending at the rear of the backrest (26) only.
 15. The seat shell of claim 12, wherein in the lower region of the backrest (26), preferably below the seat surface (25), is formed a deepening (49) designed as a finger grip.
 16. The seat shell of claim 12, wherein the shell top (20) or the shell base side (30) is producible by injection molding, by a blow process, by a cupping process and/or in a rotary casting process.
 17. The seat shell of claim 12, wherein the shell is formed in one piece. 